title: Emergence and persistence of overweight and obesity in 7- to 11-year-old children.
abstract: OBJECTIVE
  After dramatic rises in paediatric obesity, the critical period for obesity onset may now be pre-adolescence.
  
  
  METHODS
  We monitored adiposity over 4 years in 400 children aged 7-9 years recruited from schools in London. Weight, height, waist circumference (WC) and fat mass were measured annually. Weight status was defined using International Obesity Task Force (IOTF) criteria, and standardised scores and percentiles used British 1990 reference data.
  
  
  RESULTS
  BMI, WC and fat mass index all tracked strongly over time (average correlation for BMI = 0.95). Emergence of obesity was relatively uncommon: only 2% of the total sample increased from overweight to obese over the 4-year period, and this was nearly matched by the 1.3% that reduced from obese to overweight. However, more children (6%) moved from healthy weight to overweight than the reverse direction (2%). There were greater absolute gains in adiposity in children with higher baseline weight status, but this was disguised in analyses using standardised scores. Obesity was not an emergent trait in middle childhood, but rates were already high and, in absolute terms, adiposity increased more in overweight and obese than healthy weight children.
  
  
  CONCLUSIONS
  These results highlight the need for active management of obesity in middle childhood.
authors.affiliation: Coventry University, Priory Street, Coventry, UK.
authors.forename: Naomi C
authors.initials: NC
authors.lastname: Bartle
authors.forename: Claire
authors.initials: C
authors.lastname: Hill
authors.forename: Laura
authors.initials: L
authors.lastname: Webber
authors.forename: Cornelia H M
authors.initials: CH
authors.lastname: van Jaarsveld
authors.forename: Jane
authors.initials: J
authors.lastname: Wardle
mesh_terms: D000273:Adipose Tissue; D050154:Adiposity; D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D008131:London / Q000453:epidemiology; D008297:Male; D050177:Overweight / Q000453:epidemiology; D063766:Pediatric Obesity / Q000453:epidemiology*; D055105:Waist Circumference